Ultrasonic Energy Harvesting and Communication ASIC for Sensor-Integrated Machine Elements

We present an application-specific integrated circuit (ASIC) for wireless ultrasound-based sensor-integrated machine elements. The ultrasound-based communication and energy transfer allows a complete encapsulation by metal, enabling the use in harsh environments. The sensor-integrated machine element contains an external sensor, an ADC, a microcontroller, a piezo crystal, and the ASIC. The ASIC handles the physical communication layer and acts as a power source at sufficient ultrasound levels. For data transmission, various communication protocols are implemented, allowing to use backscatter as well as an active transmission scheme. The microcontroller accesses the ASIC via a Serial Peripheral Interface (SPI) and can configure multiple registers to adjust the communication protocol and the transmitted data. The ASIC is designed in a 180 nm process using only 0.26 mm(exp 2) of active chip area.